In recent years, an environment for a radio communication device to simultaneously use multiple radio communication systems of different communication schemes has been developed by a wide spread of radio communication technologies. For example, a study has been carried out to provide a radio communication device configured to be connectable to both cdma2000 n×evolution-data only (EV-DO), which is one of standards in the 3rd generation mobile system, and a wireless LAN system which is compliant with IEEE802.11 or the like.
Such a radio communication device connectable to multiple radio communication systems monitors a communication quality such as the state of a radio signal (RSSI, for example) or the throughput, the radio signal received from a radio base station currently connected to the radio communication device. The radio communication device is able to execute a handover to a radio base station in a different radio communication system before the communications in execution are cut off due to deterioration in the communication quality. (For example, Patent Document 1).
Patent Document 1: JP-A 2004-561996 (pages 11 to 12, FIG. 5)